One of the most dramatic political pivots of 2018 occurred in Ethiopia, where the sudden rise of 42-year-old Abiy Ahmed as prime minister ushered in a series of head-spinning reforms in a country long ruled by a deeply repressive regime. There is now the very real possibility that Ethiopia could make a lasting shift to democracy.

There are so many positive signs so far that most Ethiopians at home and abroad seem gripped by a sense of euphoria. But not all is well in Ethiopia. Abiy faces a number of significant obstacles to his goal of bringing a free, peaceful and genuinely competitive contest when Ethiopia holds its next elections, scheduled for 2020. Among those challenges, the most difficult is transforming the current political landscape, dominated by ethnic and tribal allegiances, to one where citizenship—loyalty to the country as a whole—transcends narrower divisions.

Abiy is the first member of the Oromo ethnic group, which makes up about a third of Ethiopia’s 100 million-strong population, to lead the country. And he has launched a reform movement, remarkably, as the nominal leader of the ruling bloc, the Ethiopian People’s Revolutionary Democratic Front, or EPRDF, which has a long track record of authoritarian rule. The EPRDF has effectively criminalized the opposition, barred critical media, engaged in ever more brutal police practices, and filled the jails with journalists and political prisoners.

A coalition of several ethnic groups, the EPRDF took power in 1991 after overthrowing Mengistu Hailemariam’s military regime. The Tigray People’s Liberation Front, or TPLF, came to dominate the EPRDF, securing the rights of the Tigray minority, which represents about 6 percent of Ethiopia’s population, at the expense of the rest of the population. In addition to the TPLF, the EPRDF includes the Oromo People’s Democratic Organization, the Amhara National Democratic Movement and the Southern Ethiopian People’s Democratic Movement.

Throughout its rule, the EPRDF has intensified ethnic divisions in Ethiopia. After taking power, it established a federal system based on the country’s ethnic differences, cementing ethnicity as the legal basis for political competition. With more than 80 ethnic groups in a country divided into nine ethnically defined regions, the potential for strife grew as Tigrayans monopolized power. As resentment with the Tigray-dominated EPRDF rose, the government cracked down harder on dissent, earning Ethiopia an ignominious spot among the world’s “Not Free” countries in Freedom House’s annual rankings.

These tensions reached deep into the ruling EPRDF. Early last year, Abiy’s Oromo Democratic Party joined forces with the Amharas to stage a coup inside the EPRDF, which propelled Abiy first to chairman of the ruling bloc and then prime minister.

Once in power, Abiy swiftly moved to introduce his momentous reforms. He reached a peace agreement with neighboring Eritrea, ending two decades of war. He released thousands of political prisoners, freed all the journalists, lifted the ban on opposition groups and reshaped the Cabinet, slashing the number of positions from 28 to 20 and naming women to half of the posts. Their role is not merely symbolic. Women were named to lead the powerful Ministry of Defense and the new Ministry of Peace, which will be responsible for intelligence and security. In addition, Ethiopia now has a woman as the mostly ceremonial president, and a woman as head of the Supreme Court.

Abiy’s empowerment of women has the potential to enlist the support of women irrespective of their ethnic allegiance, which would be crucial to the success of his reform program. As opposition leaders started returning home last year, Abiy and his representatives repeatedly declared their goal: to build a lasting democracy in Ethiopia.

But signs of trouble quickly emerged. The Tigrayans, who stand to lose the most from Abiy’s reforms, quickly objected to his peace deal with Eritrea, and outbreaks of ethnic strife suddenly escalated.

The list of disputes within Ethiopia’s ruling bloc is immense, and the potential for any of them to escalate out of control cannot be discounted.

A dizzying array of simmering ethnic conflicts have since flared up. Several disputes over land claims, for example, have turned violent. In the Tigray Region in the northwest, Amharas are claiming ownership of the Wolkite and Raya territories, resulting in clashes. Oromos and ethnic Somalis have also been fighting over grazing lands, while ethnic clashes have erupted in the cities of Awassa and Sodo in the south, leaving hundreds dead.

In the capital, Addis Ababa, tensions are growing between the Oromos, currently the most powerful members of the EPRDF, and the Amharas, their partners in pushing aside the Tigrayans. The Oromo Democratic Party has long claimed Addis Ababa as the capital of Oromia, their ethnic region. But the majority of the city’s population are ethic Amhara, who reject the Oromos’ claim.

The list of disputes is immense, and the potential for any of them to escalate out of control cannot be discounted. In addition, a likely economic slowdown would undercut Abiy’s personal appeal, which remains one of his most powerful tools.

The challenge for Abiy and his reformist allies is to strengthen Ethiopians’ bonds to the state, develop credible national institutions, and craft a credible mechanism for resolving inflamed ethnic disputes while fostering a commitment to his democratic program. He is already enacting legislative and personnel changes aimed at that goal, but he may have to go further and rewrite a constitution that institutionalized tribalism through a system of ethnic federalism.

The risks are palpable, as residents of Addis Adaba saw two months ago when a group of armed soldiers ominously marched into the prime minister’s office. The government shut down the internet as rumors of a coup began to spread. The next day, Abiy fans were delighted to see videos of the youthful president exercising with the troops—the situation defused. The prime minister said the soldiers had, in fact, come to kill him, but he listened to their complaints and it all ended on good terms.

The incident turned into more good publicity for Ethiopia’s new charismatic leader. But it is a sign of how easily his ambitions for the country could go off the rails. That would be a tragedy for the Ethiopian people, and a dispiriting development after a year in which Ethiopia was one of the few bright spots as autocrats and far-right populists made gains across the globe.

*Frida Ghitis is a world affairs columnist. A former CNN producer and correspondent, she is a regular contributor to CNN and The Washington Post. Her WPR column appears every Thursday. Follow her on Twitter at @fridaghitis.